The objective of the proposed research is the complete characterization of stimulated biomedical heavy ion beams at the BEVALAC by the direct measurement of particle fluxes and energy spectra. This is accomplished by means of a multidetector particle identification spectrometer consisting of a channel plate time-of-flight telescope, pulse ionization chambers, and a 10-element silicon detector telescope, as well as scintillation counters and multiwire proportional chambers for beam definition. The apparatus will be used initially to identify nuclear interaction products and primary beam particles emerging from a Lucite absorber, as a function of absorber thickness, along the central axis of the beam. Unmodified beams of carbon, neon and argon will be studied first, followed by spread-out, simulated biomedical beams. Computer programs under development will allow the extension of the results obtained to arbitrary configurations. The extension of this work to off-axis measurements and radiobiological experiments to be performed in a fully characterized beam will remove the dosimetric ambiguities that trouble some current radiobiological results.